problem with variable and position()

This is part of the stylesheet...


<xsl:template match="html">
	      <xsl:apply-templates select="head"/>
	      <xsl:apply-templates select="body"/>
</xsl:template>
	

<xsl:template match="head"/>
<xsl:template match="body">
                    <xsl:element name="description">
                       <xsl:apply-templates select="text()[starts-with(normalize-space
(),'Description')]" mode="description"/>
                    </xsl:element>
</xsl:template>
<xsl:template match="text()[starts-with(normalize-space(),'Description')]" 
mode="description">
                         <xsl:variable name="descPos" select="position()"/>
                         <xsl:apply-templates select="text()[position()>$descPos]"/>
                                           
</xsl:template>
<xsl:template match="text()[position()>$descPos]">
                              <xsl:value-of select="."/>
</xsl:template>  
 
I have an xhtml document with a description as a text element in the body. This 
description text start with the word "Description" and it has a variable position inside 
the input documents. I tried to store the position of the description text in the 
descPos variable to use it later, but the above stylesheet gives me an error of "Invalid 
variable reference". How could I re-write the last template so I avoid this error? 
tia,
lizet  

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